Wheeled vehicles, such as automobiles, etc, frequently include disc brake systems for slowing the motion of the vehicle. These brake systems include a rotor that rotates with the wheel to be braked. Brake pads mounted on non-rotating calipers pressed against the brake disc rotor to affect braking of the vehicle. The resultant friction converts the rotational energy or kinetic energy of the moving vehicle to thermal energy.
As a result of this energy conversion, the friction generates a substantial amount of heat each time the brake pads are applied to the rotor. The temperature of the rotor can rise significantly following frequent frictional contact between the brake pads and the rotor. It is well known that the performance of disc brake systems will deteriorate as temperature of the brake system increases.
The heat generated causes an increase in the temperature of the brake rotor and the brake pads and the brake caliper. Thermal conduction and radiation also heat up the components in the caliper such as piston, brake fluid and piston seals which isolate the brake fluid from the environment Exposure to excessive temperature can deteriorate the piston seals causing brake fluid to leak out and also will allow air to enter into the brake fluid circuit.
It is therefore desirable to keep the brake systems cooler to optimize performance of the brake system. Various methods have been utilized for this purpose. The prior arts include various types of vented disc brake rotors with fixed ventilation vanes arrangement with the cooling ability of the vanes depends largely upon the quantity of air flowing through them to dissipate the generated heat effectively. In order to achieve this, the rotor has to rotate at substantially high speed to maintain sufficient amount of forced air thru the fixed vanes passages by centrifugal action during rotation of the brake rotor when the vehicle is moving.
But however, as the brake rotor rotation speed reduces during braking process, the centrifugal airflow volume also reduces substantially and thus slows down the heat dissipation rate or causing the heat removal process ineffective. This situation further worsen under frequent braking condition where the rotor temperature tends to rise significantly to overheating condition and deteriorating the performance of the braking system leading to an unsafe driving condition.
The present invention was developed to attempt to provide improved ventilation system to a brake rotor by providing additional mechanical ventilation with use of additional centrifugal fan impeller housed inside the brake rotor. The centrifugal fan impeller rotates freely at one direction and get engaged or locked with rotor in other direction of rotation.
One way direction rotation is achieved by using single direction ball bearing which allows the centrifugal fan impeller to rotate freely at one direction only and does not allow the centrifugal fan impeller to rotate in the opposite direction. The same principle applies to bicycle chain sprocket where the sprocket in form of single direction bearing gets engaged with the wheel when the rider pedals to move the bicycle forward. While the bicycle moving forward, the sprocket or the single direction bearing disengages the pedal from the wheel when the rider stops pedaling.